All the above is true. I can't remember where I read it. But I did and remembered it because my kids have four chickens at the bottom of the garden. We sell the spare eggs to friends. There are not many spare when they have regular Eggy Dip Dip. Egg and Soldiers to you.
You do not need an ID number for under 50 birds. Therefore they don't need a stamp. However I also read somewhere that it is shortly to become compulsary to register flocks of 50 birds or more.
You cannot sell them as Free Range because that requires certification. However just let your customers see your happy birds and that is better than any label.
You should label the boxes with a use by date of not more than 28 days from lay.
You can sell them to friends for their consumption but you cannot sell them to retailers, cafe's or pubs where they are to be sold on.
Enjoy your hens they have a great attitude, I love em.